1. Field of the Invention
Embodiments of the present invention generally relate to a magnetic read head with reduced shunting and a method for manufacturing a magnetic read head with reduced shunting.
2. Description of the Related Art
Modern computer systems typically include a hard drive which may be used as mass storage for the computer system. Information in the hard drive is typically stored as magnetic charge on one or more magnetic disks within the hard drive. To read the information, the hard drive includes a magnetic read head which senses the magnetic charge as the magnetic disks spin beneath the read head.
Modern magnetic read heads typically include several layers of material deposited on a substrate. As the magnetic head passes over an area of a magnetic disk in which a magnetic charge is present, the magnetic charge may induce a detectable change in the layers of material in the magnetic read head. For example, during a read operation, a current may be applied to the layers of material in the magnetic read head. The current applied to the layers of material may create a voltage across the layers of material which is proportional the resistance of the layers of material. As the head passes over a magnetic charge on the magnetic disk, the magnetic charge may cause a change in the combined resistance of the layers of material (e.g., an increase or decrease in the resistance of the layers of material). The stored magnetic charge may then be measured via a corresponding change in the voltage across the layers of material (e.g., a corresponding increase or decrease in the voltage resulting from the current applied to the layers of material).
In order to properly read the magnetic charge stored on the magnetic disk, the read head may be manufactured with a desired sensitivity. To achieve a desired sensitivity of the magnetic read head, several aspects of the magnetic read head may be modified during manufacturing of the read head. One example of changing an aspect of the magnetic read head during manufacturing is to vary the thickness of each of the layers, each of which may be extremely thin (e.g., tens of atoms thick). As another example of adjusting the sensitivity of the magnetic read head during manufacturing, after the layers of the magnetic read head have been deposited on the substrate, the layers of the magnetic read head may be milled along a side of the read head so that the area of one or more of the layers within the magnetic read head is changed to a desired value.
In some cases, due to the thinness of the layers of the magnetic read head, milling of the layers may result in material from one or more layers being spread across other layers of the magnetic read head (referred to as a shunt). The material spread during milling may create a direct electrical connection (e.g., a short) between one or more layers of the magnetic read head. As a result of the shunt, the sensitivity of the magnetic read head may be decreased. For example, the shunted material may create a current path around the layers of the magnetic read head with a resistance which is not affected by stored magnetic charge in the magnetic disk. Because the resistance of the shunt may not be affected by stored magnetic charge in the magnetic disk, as the magnetic read head passes over stored magnetic charge, the voltage across the layers in the magnetic read head may not vary as greatly as it would if the shunt were not present. Because the voltage across the layers in the magnetic read head may not vary as greatly, the resistance change in the magnetic head due to the stored magnetic charge may be more difficult to detect.
Accordingly, what is needed is a method and magnetic read head to reduce shunting in a magnetic read head.